Illuminating apparatus



'1. ALLOCKWOOD. ILLUMINATING APPARATUS. APPLICATION FIILED JAN. 3!, 1921.

Patented July 4, 1922.

2 $HEETSSHEET JHN J. H. Lockwoov,

INVENTOR.

A TTORNEY.

J; A. LOCKWOOD.

|LLUMIN'ATING APPARATUS. APPLICATION FILED JAN-31,1921- Patented Jul 4, 1922.

2 SHEETS-SHEET 2 INVIENTORI.

A TTORNEY- l H. Loo/(W001),

p the numeral 12 indicates' :of t e lens from the umrao STATES @PATENIfF ILLUMIN ATIN G APPARATUS Toallwhom it may concern:

Be it known that I, JOHN A. LocKwoon, a citizen of the United States, residing at Fillmore, in' the State of New York, have invented certain new and usefulImprovements in Illuminating Apparatus, of which the following is a specification, reference being had to the accompanying drawings. I

his invention relates to improvements in illuminating devices and more particularly to means for distributing the light from a sin 1e source such as for example, an electric buli, so that it will be evenly distributed upon a plane surface adjacent the bulb.

.further object-of the invention is to provide a novel ahdimproved bulb structure whereby theabove result is obtained.

Other objects and advantages of the invention will become apparent in the course of the following description:

In the accompanying drawings, wherein for the purpose of illustration is shown preferred embodiments of my invention, 1

Figure 1 is a front elevation of a sign embodymg my invention,

F igure-2 is a rear elevation of the lens employed therein,

' .igures 3 and 4 are sections on the l1nes 3-3 and 4-4 of Figure 2 respectively Figures 5 to 8 illustrate lenses of unlform density and varying thickness,

Figures 9 and 10 illustrate lenses of uniform thickness and varying density, and

Figures 11 to 14 show illuminating bulbs constructed in accordance with my invention. v

Referrin now more particularly to: the drawings,t e numeral 10 indicates a source of light, the numeral 11 an objective and a lens. In the forms shown in Figures 1- to 8, the'lens is formed of translucent material resisting but not preventing the passage of light, and the thickness of the lens is varied' directly in pro ortion. to the distance of the portions source of light, that is to say, the further these portions lie from the source of light the thinner they are made, so thatthe light in passing through the lens has its rays variously obstruc'ted, the

stronger rays meeting a' stronger resistance and this resistance lessening as the distance from the light increases. and the strength of 85 n the opposite t e rays decreases, so that uplo h p d t t e projecte side of the lens from the lig Specification of Letters Patent. Application filed January 31, 1921.

county of Allegany and Serial No. 441,329.

. Patented a l a, 192a...

light is substantially uniform instrength at i T e advantages of a construction of this type when employed with transparent signs and slgns upon which flood light is employed, will be readily understood, the light from a slngle bulb affording a uniform illumination where ordinarily the illumination of the remote portions of a sign with respect to a singlebulb would be considerably decreased. As shown'in the above described figures, lensesaof "uniform translucencv but of varying thickness may be employed and the construction'of the lens may be VflIlGd-HS desired. For ekam'ple, the lens may be plano-convex, double-convex or cavoconvex. I

Instead of employing a lensflof uniform translucencyfand varym the thickness of the lens 1t will be readfl y understood that the above result will be accomplished by emand 10, in which the lens is substantially uni-form in thickness; The translucency of the lens is, however, varied through the various portions thereof distance of these portions from the source of light so that substantially the saine result is obtained thereby. This type of lens may be produced by any of the well known processes. In Figure 1, I have a vention in order that nated with a single globe. As disclosed by the sectional views thereof, a lens construction practically identical with that shown in Figure 6 is employed with the exception of the fact that the back of the lens is provided with ridges 13. In this construction the sign is painted upon the forward or outer face of the lens and the objective of light passing through the lens is accordingly the forward face thereof. It will of course be understood that such is not necessarily the case as the sign might well be painted upon an ordinary sheet of glass and this sheet arranged adjacent the lens.

In many instances it is desirable to have a bulb construction wherein the light emanating therefrom will be evenly distributed upon a given plane surface. Bulbs embodying this construction are shown in Fi res 11 and 13, in which the numeral 14 t gignates the bulb of the lobe having formed upon one side thereo a thickened translucent portion 15,- the thickness of which in proportion to the" sign embodying my in-' the samemay be illumivaries in such manner that the rays ema'nati ing from the heated wire 16 will be concentrated upon a given" plane surface of substantially equal strength. It will of course be understood that, instead of'the ;varia ble thickness of uniformly translucent material, a uniform thickness of variable translucent material may be employed as shown in Fig-.

ure 12. In combination With this structure I prefer to provide at the opposite side of the globe from the thickened portion 15 thereof; a reflector 17 which may; readily be provided by silvering this-portion of the globe. In some instances where a globe is I to be employed for illuminating double faced signs, ened portion 15 be provided at each side of the globe as illustrated in Figures 13 andl i. In employing globes of this construction it will of course be understood that the plane surface upon which the light from the globe is acting must be arranged at right angles (to a line drawn from the illuminating filament of the globe through the point of greatest density of the thickened portion 15.

From the foregoing it will be obvious that I have providedran illuminating apparatusv ment of-a single globe,

it wlll be desirable that a thick-' limit myself to the specific forms-'hereinbefore described except as hereinafter claimed.

What I claim is: a 1 1. A lens of uniform thickness and of varying translucency, the translucency 1ncreasing uniformly from the center to the edges thereof.

2. In combinatioma lens of varying translucency and a source of light, the translucenc of the, lensbeing such that the amount of lig t passing through the lens is substantially equal at any'twogiven points in a plane at right angles to a perpendicular passing through the lens and light and at that side of the lens remote from the source of light.

In testimony whereof I hereunto afiix my signature. v JOHN A. LOCKWOODI 

